Plasma measurements and effects of atrial natriuretic factor

The plasma levels of atrial natriuretic factor (ANF) a potent diuretic and vasoactive hormone, are reported to increase or remain unchanged in essential hypertension. There are, however, correlations between plasma ANF and both age and systolic blood pressure. Plasma ANF levels seem to be influenced by these two factors, as well as by chronic hypertension, and possibly by previous use of antihypertensive drugs. Injections or infusions of ANF produced a transient reduction of blood pressure with significant diuresis and natriuresis. In some cases, the hormone elicits bradycardia followed by hypotension. ANF infusions are also associated with an increase of plasma cyclic GMP, which is especially evident in essential hypertension and accompanied by enhanced diuresis and natriuresis, indicating a heightened response of these patients to ANF. Its therapeutic potential, however, remains to be determined by studies of longer duration with variable doses.